It was _______ you had done _______ made it possible for you to improve your English.
When you stand on the top of the mountain and overlook the surrounding scenery, you will find it is ______ to climb it up with effort.
A harmonious society is very important, so all the laws must be strictly______.
It is so noisy in the restaurant and hard for us to ________ a conversation.
Studies show that people are more_____ to suffer from back problems if they always sit before computer screens for long hours.
A survey of health researchers ______ that four hours of exercise every week ____ good for our health.